1. (a) Field of the Invention
The present invention relates generally to broadcast television and, more particularly, to a method and apparatus for transmitting high definition television (HDTV) programming using a digital satellite system transport.
2. (b) Description of Related Art
It is well known to transmit analog television signals over terrestrial networks. Such networks typically broadcast signals over a relatively small geographical area using the UHF or VHF frequency bands. Although still widely used, these UHF, VHF broadcast systems have significant shortcomings. For example, in order for consumers to receive a sufficiently strong signal from a terrestrial network, the consumer must typically be located near a major city (e.g., Los Angeles, Chicago or Denver). Additionally, terrestrial networks broadcast a relatively small amount of information for the bandwidth that they occupy. For the broadcast of a given program, analog terrestrial networks devote one frequency entirely to that program. Because there must be separation between transmission frequencies in a traditional broadcast system, there are relatively few programming channels available using analog terrestrial broadcast methods.
Cable television networks transmit programming channels over coaxial cable. While cable technology has greatly increased the number of channels available to a television user, the cost, materials and manpower associated with the installation and maintenance of the cable system infrastructure is quite high. These costs are typically passed on to the cable system's subscribers in their subscription fees. Additionally, cable television is not available in areas of the country where demand is insufficient.
Digital direct-to-home (DTH) satellite systems broadcast hundreds of programming channels to a very wide geographical area (e.g., the continental United States). One example of such a broadcast satellite television system is the DIRECTV.RTM. system. Broadcast satellite systems can provide many channels due to their efficient use of bandwidth. MPEG-2 video compression is one particular method of efficient bandwidth usage employed by broadcast satellite systems. The information for broadcast is converted into digital signals that are divided into packets. Each packet is assigned a header that is used to identify the information for a particular television service. The identifying information in the header is referred to as a service channel identification (SCID) or a program identification (PID). After the data have been put into packets, the packets are transmitted to a satellite, which rebroadcasts the packets over the satellite's coverage area. Each subscriber within the coverage area can receive the broadcast programming by tuning their receiver to the proper frequency and obtaining the appropriate packets based on the SCID in the header of each packet. Broadcast satellite systems eliminate the need for the massive infrastructure that cable systems require, thereby making it easy to add subscribers to the system.
The progression from terrestrial television broadcast to cable television, to DTH satellite television has allowed consumers to obtain more and more programming information while limiting the costs that are passed to the consumers. However, all of the DTH programming has been standard definition television (SDTV), which is also called conventional definition television (CDTV).
High definition television (HDTV) has a resolution of approximately twice that of SDTV in both the vertical and the horizontal dimensions. HDTV provides motion picture video resolution and CD-quality sound to a viewer at home. Additionally, the aspect ratio selected for HDTV is 16:9, which is similar to the 1.76:1 ratio used in the motion picture industry. The HDTV standard, as set forth in advanced television standards committee (ATSC) documents A/53 and A/54, specifies the use of MPEG-2 video processing in accordance with ISO/IEC standard 13818, and digital audio processing in accordance with ATSC document A/52. Plans are in place in the United States and many other countries of the world to transition from SDTV to HDTV in the near future. However, there are no known methods that enable DTH satellite systems, or any other systems (e.g., cable systems) using defined data transfer protocols, to broadcast data that is generated in accordance with HDTV standards.